INTERNET DRAFT                                               R. Housley
Intended Status: Informational                           Vigil Security
Expires: 15 March 2010                                11 September 2009

 The application/pkix-attr-cert Content Type for Attribute Certificates

Status of this Memo

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   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   This document specifies a MIME content type used to carry a single
   attribute certificate as defined in RFC 3281.

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1. Introduction

   RFC 2585 [RFC2585] defines the MIME content types for public key
   certificates and certificate revocation lists (CRLs).  This document
   specifies a MIME content type for use with attribute certificates as
   defined in RFC 3281 [RFC3281].

   Attribute certificates are ASN.1 encoded [X.680].  RFC 3281 [RFC3281]
   tells which portions of the attribute certificate must use the
   distinguished encoding rules (DER) [X.690] and which portions are
   permitted to use the basic encoding rules (BER) [X.690].  Since DER
   is a proper subset of BER, BER decoding all parts of a properly
   constructed attribute certificate will be successful.

2. IANA Considerations

   The content type for an attribute certificate is

      Type name: application

      Subtype name: pkix-attr-cert

      Required parameters: None

      Optional parameters: None

      Encoding considerations:
        In most cases, the encoding will be binary.  When the transport
        (such as SMTP) does not accommodate an unrestricted sequence of
        octets, the attribute certificate will be Base64 encoded

      Security considerations:
        An attribute certificate provides authorization information.  An
        attribute certificate is most often used in conjunction with
        public key certificate [RFC5280], and the two certificates
        should use the same encoding of the distinguished name as
        described in the Security Considerations of this document.

      Interoperability considerations:
        The content type will be used with HTTP to fetch attribute
        certificates.  Other uses may emerge in the future.

      Published specification: RFC 3281

      Applications which use this media type:
        The content type is used with MIME-complaint transport to

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        transfer an attribute certificate.  Attribute certificates
        convey authorization information, and they are most often used
        in conjunction with public key certificates [RFC5280].

      Additional information:
        Magic number(s): None
        File extension(s): .AC
        Macintosh File Type Code(s): none

      Person & email address to contact for further information:
        Russ Housley

      Intended usage: COMMON

      Restrictions on usage: none

      Russ Housley <>

      Intended usage: COMMON

      Change controller:
      The IESG <>

3. Security Considerations

   Attribute certificate issuers must encode the holder entity name in
   exactly the same way as the public key certificate distinguished
   name.  If they are encoded differently, implementations may fail to
   recognize that the attribute certificate and public key certificate
   belong to the same entity.

4. References

4.1. Normative References

   [RFC3281]  S. Farrell, S., and R. Housley, "An Internet Attribute
              Certificate Profile for Authorization", RFC 3281,
              April 2002.

4.2. Informative References

   [RFC2585]  Housley, R., and P. Hoffman, " Internet X.509 Public Key
              Infrastructure Operational Protocols: FTP and HTTP",
              RFC 2585, May 1999.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

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   [RFC5280]  Cooper, D., S. Santesson, S. Farrell, S. Boeyen,
              R. Housley, W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation
              List (CRL) Profile", RFC 5280, May 2008.

   [X.680]    ITU-T Recommendation X.680 (2002) | ISO/IEC 8824-1:2002,
              Information technology - Abstract Syntax Notation One
              (ASN.1):  Specification of basic notation.

   [X.690]    ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002,
              Information technology - ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules

Authors' Addresses

   Russell Housley
   Vigil Security, LLC
   918 Spring Knoll Drive
   Herndon, VA 20170

Housley                                                         [Page 4]